Investigation of cytomegalovirus and human herpes viruses 6 and 7 as possible causative antigens in psoriasis

Psoriasis is probably a T-cell-mediated autoimmune disease, Infectious mode ls of autoimmune diseases have been proposed and in psoriasis, it has been suggested that there may be molecular mimicry between streptococcal antigen s and epidermal keratins. The immunological profile of stable psoriasis pla ques suggests, however, that viral antigens may be important. We investigat ed, using polymerase chain reaction techniques, whether DNA from either cyt omegalovirus (CMV) or human herpes viruses (HHV) 6 and 7 is present in the skin of patients (n=10) with chronic plaque psoriasis. We also investigated 29 patients for the presence of serum Ige to CMV, We found no evidence of CMV or HHV 7 DNA in psoriasis plaques although DNA for HHV 6 was detected i n both involved and uninvolved skin in I out of 10 patients, There was no s tatistically significant increase in prior CMV infection, as assessed by th e presence or absence of serum IgG to CMV, in psoriasis, compared to our lo cal population, Although there is circumstantial evidence that viral antige ns may be important in the pathogenesis of psoriasis we found no evidence t o link infection with CMV or HHV 6 and 7 with subsequent development of chr onic plaque psoriasis.